bhz5004

So this issue happened a few weeks ago and I cant figure it out. Nor can my local mechanic.

So the car will go into accessory mode fine, battery is charged and good. But whenever I hit the brake pedal when in accessory mode, the light never switches from red to green. I tried to replace the brake light switch and that didn't change anything. The battery in the fob is good too.

The only way for me to get the car started is by using a relay bypass on the R5 starter relay. The car turns over fine, hasnt failed once.(additionally, i swapped the r5 relay with a known working one and still didnt help)

Does anyone have any idea where else to look. I read some places that the push button may need replaced, but I'd like to get a better idea before I give up and send it to a dealership.


Thanks!
Ben

Wilson2000

Just spitballing here...Was any work done to your ES prior to the non-starting issue? Have you tried disconnecting the battery so the electrical system is forced to re-boot? Does your battery test at over 12.6 volts while disconnected? Even at 12.4V your battery is only 75% charged. If you don't read 12.6V, charge your battery and test again with the positive cable both connected and disconnected. If you have a large drop with it connected, you may have a short somewhere.

bhz5004

Thanks for the reply.

No work was done prior to the issue presenting itself. We tried a whole new battery and that still didn't help. I was starting to think there might be a short somewhere but I have no idea where to start. Curious how much a lexus dealership would charge to fix a short...

I'll keep poking around and see what I can find, but it isnt looking good for me. lol

Wilson2000

Do you have a VOM to check the battery voltage, connected vs disconnected? Try putting the tranny in neutral and start. There's a switch that tells the ECU if the vehicle is in park or neutral (otherwise don't start). You can test the switch with a VOM as well, but it would require a wiring diagram to know where the switch leads can be accessed. Worst case, you can disassemble the shifting console to test the switch.

I'm flying blind here as I decided not to buy the factory shop manuals unless I needed them, and after nine years of ownership, not one issue has come up on my wife's ES!